Alert archive / Maryland / Calvert County
Weather alerts in Calvert County, Maryland, 2020
147 weather alerts in 2020, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Calvert County and its neighbors
Each county as a circle sized by its count in 2020. Tap one for its archive.
- Alerts
- 147
- Warnings
- 54
- Watches
- 28
- Advisories
- 33
- Busiest month
- July40 alerts
- Busiest day
- August 4, 202010 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
2 of 3 tornado warnings covering Calvert County in 2020 had a tornado report inside them; 2 of 2 tornado reports fell inside a warning, on average 17 minutes after it went out.
Calvert County, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 3 | 2 | 33% | 2 | 100% | 17 min |
| Severe thunderstorm warnings | 29 | 20 | 31% | 13 | 85% | 17 min |
| Flash flood warnings | 4 | 3 | 25% | 1 | 0% |
Each office's whole area, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Baltimore/Washington: tornado warnings | 27 | 6 | 78% | 15 | 47% | 9 min |
| NWS Baltimore/Washington: severe thunderstorm warnings | 456 | 314 | 31% | 1,047 | 79% | 23 min |
| NWS Baltimore/Washington: flash flood warnings | 66 | 34 | 48% | 130 | 90% | 72 min |
An office's figures cover every county it serves, including across state lines.
Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.
The alerts
Every alert, in the order issued. Times are local, Eastern Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jan 12, 12:57 AM EST | Severe Thunderstorm Warning | LWX | 28 min |
| Feb 5, 3:23 PM EST | Flood Watch | LWX | 35 hr |
| Feb 6, 9:30 PM EST | Wind Advisory | LWX | 20 hr |
| Feb 7, 8:48 AM EST | Severe Thunderstorm Warning | LWX | 27 min |
| Feb 7, 9:16 AM EST | Severe Thunderstorm Warning | LWX | 13 min |
| Feb 26, 12:54 AM EST | Dense Fog Advisory | LWX | 8 hr |
| Mar 3, 10:52 PM EST | Mesoscale Discussion | SPC | 113 min |
| Mar 3, 11:48 PM EST | Severe Thunderstorm Warning | LWX | 42 min |
| Mar 27, 3:31 AM EDT | Coastal Flood Advisory | LWX | 10 hr |
| Mar 29, 11:16 PM EDT | Dense Fog Advisory | LWX | 5 hr |
| Mar 31, 8:58 PM EDT | Coastal Flood Advisory | LWX | 19 hr |
| Apr 4, 4:37 PM EDT | Coastal Flood Advisory | LWX | 35 hr |
| Apr 7, 2:57 PM EDT | Mesoscale Discussion | SPC | 93 min |
| Apr 8, 4:22 AM EDT | Severe Thunderstorm Warning | LWX | 38 min |
| Apr 9, 11:09 AM EDT | Mesoscale Discussion | SPC | 66 min |
| Apr 9, 12:01 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Apr 12, 12:35 PM EDT | High Wind Warning | LWX | 26 hr |
| Apr 12, 12:35 PM EDT | Wind Advisory | LWX | 29 hr |
| Apr 13, 10:34 AM EDT | Mesoscale Discussion | SPC | 86 min |
| Apr 13, 11:33 AM EDT | Tornado Watch | SPC | 5 hr |
| Apr 13, 1:20 PM EDT | Mesoscale Discussion | SPC | 85 min |
| Apr 16, 1:19 PM EDT | Freeze Warning | LWX | 20 hr |
| Apr 18, 1:19 PM EDT | Frost Advisory | LWX | 20 hr |
| Apr 21, 4:04 AM EDT | Freeze Warning | LWX | 27 hr |
| Apr 21, 12:23 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Apr 29, 4:24 AM EDT | Flood Watch | LWX | 39 hr |
| Apr 29, 7:47 AM EDT | Coastal Flood Advisory | LWX | 52 hr |
| Apr 30, 9:17 AM EDT | Wind Advisory | LWX | 5 hr |
| May 3, 7:35 PM EDT | Flash Flood Watch | LWX | 5 hr |
| May 3, 11:17 PM EDT | Severe Thunderstorm Warning | LWX | 43 min |
| May 9, 3:36 AM EDT | Frost Advisory | LWX | 28 hr |
| May 19, 2:58 PM EDT | Coastal Flood Advisory | LWX | 42 hr |
| May 26, 8:03 AM EDT | Dense Fog Advisory | LWX | 3 hr |
| May 27, 6:45 AM EDT | Dense Fog Advisory | LWX | 3 hr |
| Jun 4, 8:50 PM EDT | Severe Thunderstorm Warning | LWX | 40 min |
| Jun 22, 4:49 PM EDT | Severe Thunderstorm Warning | LWX | 41 min |
| Jun 25, 6:09 PM EDT | Mesoscale Discussion | SPC | 96 min |
| Jun 27, 5:30 PM EDT | Mesoscale Discussion | SPC | 60 min |
| Jul 1, 12:29 PM EDT | Severe Thunderstorm Warning | LWX | 46 min |
| Jul 1, 1:07 PM EDT | Severe Thunderstorm Warning | LWX | 22 min |
| Jul 1, 1:46 PM EDT | Mesoscale Discussion | SPC | 119 min |
| Jul 1, 3:14 PM EDT | Severe Thunderstorm Warning | LWX | 17 min |
| Jul 5, 1:50 PM EDT | Mesoscale Discussion | SPC | 115 min |
| Jul 6, 12:33 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 6, 12:41 PM EDT | Flash Flood Watch | LWX | 15 hr |
| Jul 6, 1:38 PM EDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jul 6, 4:33 PM EDT | Mesoscale Discussion | SPC | 117 min |
| Jul 6, 6:25 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 6, 8:39 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 6, 10:14 PM EDT | Severe Thunderstorm Warning | LWX | 46 min |
| Jul 6, 10:50 PM EDT | Flash Flood Warning | LWX | 4 hr |
| Jul 6, 10:57 PM EDT | Severe Thunderstorm Warning | LWX | 34 min |
| Jul 7, 12:10 AM EDT | Flash Flood Warning | LWX | 4 hr |
| Jul 7, 2:44 AM EDT | Areal Flood Warning | LWX | 6 hr |
| Jul 7, 4:06 AM EDT | Areal Flood Warning | LWX | 6 hr |
| Jul 7, 8:48 AM EDT | Areal Flood Warning | LWX | 9 hr |
| Jul 18, 2:59 PM EDT | Heat Advisory | LWX | 29 hr |
| Jul 19, 2:47 PM EDT | Excessive Heat Watch | LWX | 5 hr |
| Jul 19, 2:47 PM EDT | Heat Advisory | LWX | 29 hr |
| Jul 20, 8:34 AM EDT | Excessive Heat Warning | LWX | 11 hr |
| Jul 20, 8:06 PM EDT | Heat Advisory | LWX | 24 hr |
| Jul 21, 7:44 PM EDT | Severe Thunderstorm Warning | LWX | 61 min |
| Jul 22, 12:07 AM EDT | Heat Advisory | LWX | 18 hr |
| Jul 22, 10:48 AM EDT | Mesoscale Discussion | SPC | 117 min |
| Jul 22, 12:01 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 22, 3:18 PM EDT | Mesoscale Discussion | SPC | 87 min |
| Jul 22, 4:05 PM EDT | Severe Thunderstorm Warning | LWX | 55 min |
| Jul 22, 4:34 PM EDT | Severe Thunderstorm Warning | LWX | 56 min |
| Jul 22, 4:55 PM EDT | Mesoscale Discussion | SPC | 95 min |
| Jul 23, 2:43 AM EDT | Heat Advisory | LWX | 16 hr |
| Jul 27, 7:31 PM EDT | Heat Advisory | LWX | 23 hr |
| Jul 28, 3:19 PM EDT | Mesoscale Discussion | SPC | 116 min |
| Jul 28, 5:19 PM EDT | Severe Thunderstorm Warning | LWX | 41 min |
| Jul 28, 5:57 PM EDT | Severe Thunderstorm Warning | LWX | 37 min |
| Jul 30, 1:06 PM EDT | Heat Advisory | LWX | 6 hr |
| Jul 30, 7:14 PM EDT | Severe Thunderstorm Warning | LWX | 46 min |
| Jul 30, 7:42 PM EDT | Severe Thunderstorm Warning | LWX | 48 min |
| Jul 31, 1:04 PM EDT | Mesoscale Discussion | SPC | 116 min |
| Aug 1, 7:05 PM EDT | Mesoscale Discussion | SPC | 115 min |
| Aug 2, 3:28 PM EDT | Flash Flood Watch | LWX | 45 hr |
| Aug 2, 4:56 PM EDT | Tropical Storm Watch | LWX | 18 hr |
| Aug 2, 5:19 PM EDT | Coastal Flood Watch | LWX | 24 hr |
| Aug 2, 9:47 PM EDT | Severe Thunderstorm Warning | LWX | 43 min |
| Aug 3, 2:13 AM EDT | Severe Thunderstorm Warning | LWX | 26 min |
| Aug 3, 2:55 AM EDT | Severe Thunderstorm Warning | LWX | 23 min |
| Aug 3, 5:29 AM EDT | Tropical Storm Warning | LWX | 36 hr |
| Aug 3, 5:15 PM EDT | Coastal Flood Warning | LWX | 29 hr |
| Aug 4, 1:41 AM EDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 4, 2:26 AM EDT | Tornado Watch | SPC | 9 hr |
| Aug 4, 5:15 AM EDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 4, 6:44 AM EDT | Tornado Warning | LWX | 31 min |
| Aug 4, 6:57 AM EDT | Flash Flood Warning | LWX | 4 hr |
| Aug 4, 7:17 AM EDT | Tornado Warning | LWX | 28 min |
| Aug 4, 7:32 AM EDT | Flash Flood Warning | LWX | 4 hr |
| Aug 4, 7:42 AM EDT | Tornado Warning | LWX | 8 min |
| Aug 4, 10:47 AM EDT | Areal Flood Warning | LWX | 17 hr |
| Aug 4, 11:20 AM EDT | Areal Flood Warning | LWX | 21 hr |
| Aug 5, 10:51 PM EDT | Flash Flood Watch | LWX | 25 hr |
| Aug 6, 5:28 AM EDT | Areal Flood Warning | LWX | 94 min |
| Aug 7, 3:46 AM EDT | Flash Flood Watch | LWX | 21 hr |
| Aug 11, 3:19 PM EDT | Flash Flood Watch | LWX | 52 hr |
| Aug 12, 1:15 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 13, 8:32 AM EDT | Areal Flood Warning | LWX | 6 hr |
| Aug 13, 9:25 AM EDT | Areal Flood Warning | LWX | 5 hr |
| Aug 15, 10:22 PM EDT | Flash Flood Watch | LWX | 11 hr |
| Aug 17, 9:10 AM EDT | Coastal Flood Advisory | LWX | 21 hr |
| Aug 25, 3:10 PM EDT | Mesoscale Discussion | SPC | 95 min |
| Aug 25, 3:34 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 25, 7:07 PM EDT | Mesoscale Discussion | SPC | 113 min |
| Aug 25, 7:51 PM EDT | Severe Thunderstorm Warning | LWX | 39 min |
| Aug 25, 8:50 PM EDT | Mesoscale Discussion | SPC | 115 min |
| Aug 28, 1:37 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 28, 6:55 PM EDT | Severe Thunderstorm Warning | LWX | 33 min |
| Aug 28, 7:41 PM EDT | Severe Thunderstorm Warning | LWX | 49 min |
| Aug 28, 7:50 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 29, 2:43 AM EDT | Areal Flood Warning | LWX | 12 hr |
| Aug 29, 12:08 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Sep 2, 3:37 PM EDT | Mesoscale Discussion | SPC | 53 min |
| Sep 2, 6:43 PM EDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Sep 3, 3:06 PM EDT | Mesoscale Discussion | SPC | 114 min |
| Sep 3, 3:42 PM EDT | Tornado Watch | SPC | 6 hr |
| Sep 3, 5:27 PM EDT | Severe Thunderstorm Warning | LWX | 63 min |
| Sep 9, 2:15 PM EDT | Flash Flood Watch | LWX | 30 hr |
| Sep 10, 4:33 PM EDT | Areal Flood Warning | LWX | 5 hr |
| Sep 12, 6:37 PM EDT | Coastal Flood Advisory | LWX | 12 hr |
| Sep 26, 11:55 PM EDT | Dense Fog Advisory | LWX | 10 hr |
| Oct 21, 1:51 AM EDT | Dense Fog Advisory | LWX | 9 hr |
| Oct 23, 3:26 AM EDT | Dense Fog Advisory | LWX | 8 hr |
| Oct 27, 1:36 AM EDT | Dense Fog Advisory | LWX | 7 hr |
| Oct 28, 3:05 PM EDT | Flood Watch | LWX | 25 hr |
| Oct 29, 8:50 AM EDT | Wind Advisory | LWX | 11 hr |
| Oct 31, 6:59 PM EDT | Wind Advisory | LWX | 44 hr |
| Nov 6, 4:20 AM EST | Dense Fog Advisory | LWX | 5 hr |
| Nov 6, 11:45 PM EST | Dense Fog Advisory | LWX | 9 hr |
| Nov 11, 10:46 AM EST | Flash Flood Watch | LWX | 16 hr |
| Nov 11, 9:46 PM EST | Areal Flood Warning | LWX | 27 hr |
| Nov 15, 3:33 PM EST | Mesoscale Discussion | SPC | 2 hr |
| Nov 15, 5:35 PM EST | Severe Thunderstorm Watch | SPC | 5 hr |
| Nov 15, 8:16 PM EST | Severe Thunderstorm Warning | LWX | 59 min |
| Nov 30, 12:26 PM EST | Mesoscale Discussion | SPC | 3 hr |
| Nov 30, 1:07 PM EST | Tornado Watch | SPC | 6 hr |
| Nov 30, 1:28 PM EST | Severe Thunderstorm Warning | LWX | 28 min |
| Dec 5, 3:37 AM EST | Areal Flood Warning | LWX | 12 hr |
| Dec 15, 11:54 AM EST | Flood Watch | LWX | 34 hr |
| Dec 23, 4:27 AM EST | Flash Flood Watch | LWX | 47 hr |
| Dec 23, 9:07 PM EST | Wind Advisory | LWX | 29 hr |
| Dec 24, 5:54 PM EST | Coastal Flood Advisory | LWX | 24 hr |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
| Product | Alerts |
|---|---|
| Severe storms | |
| Severe Thunderstorm Warning | 29 |
| Tornado Warning | 3 |
| Severe Thunderstorm Watch | 7 |
| Tornado Watch | 4 |
| Mesoscale Discussion | 32 |
| Flooding | |
| Areal Flood Warning | 12 |
| Flash Flood Warning | 4 |
| Flash Flood Watch | 10 |
| Flood Watch | 4 |
| Heat | |
| Excessive Heat Warning | 1 |
| Excessive Heat Watch | 1 |
| Heat Advisory | 7 |
| Cold | |
| Freeze Warning | 2 |
| Frost Advisory | 2 |
| Wind and dust | |
| High Wind Warning | 1 |
| Wind Advisory | 6 |
| Fog and smoke | |
| Dense Fog Advisory | 10 |
| Tropical | |
| Tropical Storm Warning | 1 |
| Tropical Storm Watch | 1 |
| Coast and beach | |
| Coastal Flood Warning | 1 |
| Coastal Flood Watch | 1 |
| Coastal Flood Advisory | 8 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20192021
Sources
National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.